Microbiology: Unit III

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Microbiology Unit III

• By Julie E. Davis BSN, RN
• 08-09

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Factors that Promote Growth of Microbes

• Darkness
• Warmth
• Moisture
• Food
• Oxygen
• Grow best at body temperature

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Nonspecific Bodily Defenses

• Intact skin
• Moist mucous membranes cilia
• Macrophages phagocytes
• Saliva tears (enzymes)
• Stomach/gastric acids, intestinal bacteria, bile
• Vaginal secretions (acidic pH)
• Urine (flushes urethra)
• Chemical agents in the immune system (interferon)

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Specific/Immune Defenses

• Specific Defenses come from your immune system
• Immune system defends against various invaders
  called antigens
• Antigens are proteins foreign to your body such
  as bacteria, fungi, viruses other infectious
  agents
• Immunity is the bodys resistance to infection

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Types of Vaccines

• Live attenuated- MMR, polio, BCG (for TB)
• Dead inactivated-Hep B, influenza, anthrax
• Bacterial capsular antigens-Pneumococcal vaccine
• Bacterial toxoids-tetanus

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Types of Immunity (Active or Passive)

• Active Immunity (ATB produced by body)
• 1. Natural-acquired by infection with an antigen,
  resulting in the production of antibiotics
  (lifelong protection)
• Ex getting the Chickenpox
• 2. Artificial-acquired by immunization with the
  antigen, such as an attentuated or (weakened)
  live virus vaccine stimulates body to produce
  its own antibodies (long-term protection)
• Ex MMR, polio vaccine, DPT, Hep B vaccine
• Immunizations break the cycle of infection by
  altering the defenses of the host

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Types of Immunity (Active or Passive)

• Passive Immunity (ATB are acquired from another
  source)
• 1. Natural-acquired by transfer of maternal
  antibodies to the fetus or neonate via the
  placenta or breast milk (6 mo-1 year)
• Ex Neonate is initially protected against MMR
  if mother is immune
• 2. Artificial-acquired by direct administration
  of actual antibodies or antitoxins found in
  immune globulin (short-term protection, 2-3
  weeks)
• Ex gamma globulin injection after Hep A
  exposure, snake bite anti-venom

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CDC Clinical Guidelines

• Periodically wash hands thoroughly with soap
  water more often if visibly dirty
• Use a alcohol-based hand sanitizer in between
  before after contact with each patient
• Hands should be washed before donning gloves
  after glove removal

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Drug Resistant Microorganisms

• Increase in nosocomial drug-resistant organisms
• MRSA, VRE, resistant TB
• Causes
• Poor handwashing failure to glove
• Over-prescribing of antibiotics
• Misuse of antibiotics

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Patient Teaching Drug-Resistant Microorganisms

• Take ALL of your prescribed antibiotics
  (Rationale Prolonged illness development of
  resistance)
• Do NOT take antibiotics for viral infections
  (Rationale ATB are used for treatment of
  bacterial infections only)
• Do NOT insist on the newest most powerful
  antibiotics unless necessary (Rationale Can
  promote development of resistance)

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Methods of Control of Microbes

• Antiseptics
• Chemical that destroys bacteria or inhibits their
  growth on a living being
• Ex alcohol and hydrogen peroxide, iodine
• Disinfectants
• Chemical used on inanimate objects
• Ex Lysol and bleach
• Bactericides
• Chemical with antibacterial effects that kill
  bacteria by disrupting metabolic processes
• Bleach Lysol are examples of bactericides that
  will also destroy certain viruses like influenza
• 10 bleach will inactivate the HIV virus

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Control of Microbes (cont)

• Bacteriostatics
• Antibacterial chemicals that do not destroy
  bacteria, but rather inhibit their reproduction
  slow their growth
• Some chemicals may be both disinfectant
  antiseptic like alcohol. Can be used on living
  being or inanimate object

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Control of Microbes (cont)

• Sterilization is a process that destroys all
  living organisms
• Environmental surfaces are disinfected
• Surgical instruments are sterilized
• Most medical lab products are sterilized by
  autoclave
• All equipment must be sterile to determine
  causative agent

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Methods of Sterilization

• Autoclave
• Chamber in which steam is generated under
  pressure-also kills difficult bacterial spores
• Ionizing radiation
• Radiation waves (gamma rays beta rays) to
  sterilize plastics or food
• Either lethal or cause mutations damaging DNA or
  protein
• Ex irradiated chicken
• Boiling Water
• Does not destroy spores some viruses
• Boil _at_ 212 for 15-20 minutes
• Dry Heat
• Two hours in the oven 220 or 45 minutes at 350

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Asepsis

• Medical Asepsis
• AKA clean technique
• Inhibits growth spreading of pathogenic
  organisms
• Use of Blood Body Fluid Precautions
• Surgical Asepsis
• AKA sterile technique, used in OR
• The absence of all microorganisms their
  spores
• Slightest break in technique results in assumed
  contamination

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Public Health Measures Safe Food

• Standards must be followed by supermarkets
  restaurants (only five fatal cases of botulism
  since 1925)
• Pasteurization-milk is ideal environment for
  bacteria
• Heated to 145 degrees for 30 minutes
• Pathogens are killed, not all bacteria are
  destroyed
• Newer methods may use higher temps for shorter
  periods of time

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Public Health MeasuresSafe Food (cont)

• Food related outbreak-public health will trace it
  to its cause
• Food is NOT sterile. Meat should be thoroughly
  cooked fruits vegetables thoroughly washed or
  peeled if eating raw

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Public Health MeasuresSafe Water

• Reliable supply of clean water depends on
• Diverting human sewage away from water supply
• Chlorinating water intended for human consumption
• However, well spring water is still considered
  safe.
• Cleaned by natural filtration system (sand
  rocks in Earth layers)
• Some molds get through but hydrochloric acid in
  stomach usually destroys them

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Standard PrecautionsTier I

• Should be used on all patients all the time!!!
  (Not just with the ones you know are
  sick.)
• Hands are to be washed before donning gloves
  after removing them.
• Gloves are to be worn when there is a chance of
  coming into contact with body fluids of any type
  (saliva, urine, feces, blood, drainage,
  secretions, etc.)
• The only time that gloves are not worn is for
  contact with intact skin or unsoiled articles

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Standard Precautions (cont)

• Impermeable gowns are to be worn when your
  clothing may become soiled with body fluids.
• Masks are worn when contact with respiratory
  droplet secretions is anticipated.
• Protective eyewear is added when there is the
  possibility of splashing body fluids.
• See Figure 9-2 (Ramont)

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Transmission-BasedPrecautions Tier II

• Used in addition to Standard Precautions in pt
  with known/suspected infection
• Contact can be transmitted by touching
  contaminated items (MRSA VRE)
• Airborne- small nuclei that may remain suspended
  in air can travel around the room
• Droplet- particles that can travel short
  distances around room from a cough, sneeze, etc.

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Transmission-Based Precaustions Tier II

• Considerations
• Isolation practices
• Transporting the client
• Personal Protective Equipment (PPE)
• Cleaning of Reusable Equipment
• Disposal of Soiled Equipment

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Nursing Process The Client w/ an Infection

• Assessment (Collect Information)
• Diagnosis (Made a nursing diagnosis)
• Planning (Set goals)
• Implementation/Intervention (Perform appropriate
  care actions)
• Evaluation (Determine if plan should be revised)

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Nursing Process Assessment

• Collect Information
• Objective info what you can observe signs
  such as drainage or redness
• Subjective info what they report to you
  symptoms such as headache or nausea
• Obtain client history
• Perform physical assessment

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Nursing Process Diagnosis

• Nursing diagnosis
• Risk for Infection
• They may be many others related to the infection

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Nursing Process Planning

• Planning Set goals that you wish for the
  patient to achieve
• Restore maintain body defenses against
  infection
• Prevent the further spread of infection

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Nursing Process ImplementationInterventions

• Nursing Actions Rationales (why)
• Dispose of linens, dressings waste
  appropriately (To prevent the transfer of the
  microorganism to others)
• Wear gloves (To prevent contamination transfer
  of microorganism)
• Wash hands (To prevent spread of infection)
• Use sterile technique for invasive procedures (To
  prevent contamination of bodys sterile areas,
  i.e. bladder, blood)

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Nursing Process Evaluation

• Evaluation
• Did plan work?
• Have you met your goals?
• Does plan need to be revised?

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Patient Education

• Teach clients about handwashing
• Educate about immunizations

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Practicing Sterile Technique

• A sterile field is a microorganism-free area that
  must be created
• Wear sterile gloves gown when appropriate
• If the field becomes wet it is contaminated
• If anything unsterile comes in contact w/ the
  sterile field, it is contaminated when in doubt
  it is contaminated
• Never reach across or turn your back on a sterile
  field

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Supplemental Readings

• Ramont, R. Niedringhous, D. (2008). Fundamental
  nursing care. (2nd Ed.). Upper Saddle River, New
  Jersey Pearson Prentice Hall.
• Chapter 9, pp. 154-162.